The present invention relates to a small loader that has a unitized central body forming a frame, and which has drive units on the body for propelling the loader. The drive units are, as shown, right and left-hand track assemblies that have mounting plates on which drive components can be assembled apart from the loader body and then bolted into place. Preassembly of the drive units permits efficient assembly.
Prior skid steer loaders have used a unitized central body or frame that mounts drive hydraulic motors, and then has chain drives going to front and rear wheels. The axles and wheel hubs are individually mounted onto the central body during assembly of the loader. Thus, while a unitized body is provided, the drives are not assembled as a unit and then mounted to the body.
Additionally, various track drive units for loaders have used sub-frames for mounting the bogie wheels, but the drive unit is not preassembled on a mounting plate. A skid steer loader that has a center body is shown in U.S. Pat. No. 4,955,455, but the drive units are all part of the frame as it is built-up, and the wheels are added at the very end of assembly.
The present invention relates to a small loader, for example a walk behind loader that is, in the form shown, track propelled by drive units on opposite sides of a center body or frame. The drive and propelling units are at least partially preassembled so the major drive components and supports are on a mounting plate. The plate is then bolted onto the sides of the body or frame. The drive motor, drive sprocket and the track can be assembled last, after the plate is attached to the body, or can be preassembled, since the motor bolts to the mounting plate and do not fasten on the side wall of the body. The drive unit can be preassembled as a unit including at least the major components, and merely bolted in place.
For track-drive units, as shown, this arrangement is particularly advantageous in that the frame for the bogie wheels, and the frame slidably holding the spring loaded front idler wheel or sprocket (or the rear idler in the second form of the invention) can be welded to the mounting plate. The parts are preassembled on the frame and mounting plate, and then the plate is bolted on as a unit to the loader body. When desired, and if the weight of the assembly is not excessive, the drive motor can be bolted to the mounting plate, the drive sprocket placed on the motor shaft and the track put over the drive sprocket and idler wheel, so all components of each drive unit are preassembled on the mounting plate.
A modified form of the invention utilizes a drive motor and sprocket that are raised above a pair of idler wheels that support the bottom portion of the track, and the arrangement can be to use a rear tightener wheel, with a stationary forward wheel. However, the guide wheels or end sprockets for the track can be mounted on a mounting plate as in the first form of the invention, with slight modifications in the construction of the frame and supports for the pivoting loader arm.
If drive wheels and rubber tires are used, the same concept can be utilized. The components that are necessary for driving the wheels and tires can be mounted onto a plate, and then the plate in turn bolted directly to the frame. For skid steer loaders, drive chains from one motor can be used for driving both the front and rear wheels and tires and would be on the outside of the mounting plate. The wheels and tires can be mounted on sub axles cantilevered from the mounting plate. Coupling a hydraulic drive motor to the drive sprocket through provided openings in the frame and the mounting plate can easily be achieved.